The bread one eats in the morning or for breakfast as the first "meal" of the day, most typically when hungover/recovering from a messy and drunken endeavor

Jon: "Hey Sarah I could really do with some Morning Bread, my head is just thumping from last night. You seen it anywhere?"
Sarah: "Sure here it is, I just had some myself. Found it in a saucepan under the table- last night must've been messy!"